Synthetic silver halide emulsion binder

ABSTRACT

A PHOTOSENSITIVE SILVER HALIDE EMULSION WHEREIN THE EMULSION BINDER COMPRISES A QUATERNARY AMMONIUM ACRYLATE CARBOXYBETAINE POLYMER OR COPOLYMER.

nited' States Patent Oflice ABSTRACT OF THE DISCLOSURE A photosensitivesilver halide emulsion wherein the emulsion binder comprises aquaternary ammonium 'acrylate carboxybetaine polymer or copolymer.

BACKGROUND OF THE INVENTION This invention relates to photography andmore particularly, to novel photosensitive photographic elements,particularly novel photosensitive emulsions.

As a result of the known disadvantages of gelatin, in particular, itsvariable photographic properties and its fixed physical properties, forexample, its diffusion characteristics; much effort has been expended inthe past in order to replace gelatin with a suitable synthetic colloidbinder for photographic silver halide emulsions. Many syntheticpolymeric materials have heretofore been suggested as peptizers forsilver halide emulsions, however, these have generally not functionedsatisfactorily and frequently have not fulfilled all of the basicrequirements for a photosensitive silver halide emulsion binder listedfollowing:

'(1) Absent (or constant) photographic activity;

(2) Ability to form an adsorption layer on microcrystals of silverhalide permitting stable suspensions to be obtained;

(3) Ability to form adsorption layers as described in (2) above which donot prevent growth of silver halide microcrystals during physicalripening; and

(4) Solubility in water solution.

In addition, hithertofore, much emphasis has been placed on the abilityof the synthetic polymeric material to mix with gelatin, 'as thisproperty has been critical for employment in partial substitutionreactions with gelatin. Consequently, many synthetic polymers of theprior art have been materials which allow for the growth of silverhalide crystals only in the presence of gelatin. For example, =Dykstraand Whitely, US. Pat. No. 3,411,912 dis closes a photographiccomposition comprising a waterinsoluble interpolymer having units of asulfobetaine monomer. These interpolymers do not exhibit good peptizingaction for silver halide and therefore emulsions in which they areemployed must contain another binding agent which exhibits the requiredpeptizing action, such as gelatin. j

Great Britain Pats. 765,893 and 786,345 describe watersoluble copolymerscomprising units of a carboxybetaine monomer, which copolymers aresuitable for employment as synthetic silver halide emulsion binders;however, these copolymers are to be distinguished from the acrylatepolymers of the instant invention in that the former are amides; and notesters, of acrylic acid.

Copending Application Ser. No. 320,452, filed Jan. 2, 1973 describesphotographic silver halide emulsion binders of quaternary ammonium alkylacrylate polymeric salts having counter-ions or anions bonded to thepolymer by ionic forces and which may be relatively easily re moved orinterchanged, Whereas the present invention is directed to silver halideemulsions employing polymers which are inner salts, or betaines having acarboxyl group covalently bonded through a carbon chain to thequaternized nitrogen atom.

Patented Aug. 27, 1974 My copending application Ser. No. 294,979, filedOct. 4, 1972 as a continuation-in-part of now-abandoned application Ser.No. 103,305, filed Dec. 31, 1970, discloses the employment of aminealkyl acrylate polymers as colloid binders in photographic silver halideemulsions; however, there is no mention or suggestion therein that thecorresponding quaternary ammonium compounds, which would be expected bythose skilled in the chemical arts to behave quite differentlychemically than their amine analogs, would be suitable for suchemployment.

SUMMARY OF THE INVENTION The'present invention is directed to aphotosensitive silver halid emulsion wherein the silver halide crystalsare disposed in a synthetic polymeric binder comprising a water-solublefilm-forming polymer having in its structure repeating units representedby the formula:

R1 B: it l 4 ia-rlrimcoo wherein R is hydrogen, a lower alkyl group,i.e., 1-4 carbon alkyl group, preferably methyl or ethyl, or a halogen,i.e., chloro, bromo, or iodo; R is hydrogen, a lower alkyl group, ahalogen or cyano group; R and R each is a lower alkylene group, i.e., 14carbon alkylene group or a lower cycloalkylene group, i.e., 3-6 carboncyclo alky-lene group; and R and R5 each is a lower alkyl or a lowercycloal-kyl group, i.e. a 3-6 cycloalkyl group; or acombination of Rand/or R and/or R and/or -R represents the atoms necessary to complete a3 to 8-membered 'heterocyclic ring structure. The above-describedpolymers are herein designated as quaternary ammonium acrylatecarboxybetaine polymers, or for convenience, simply carboxybetainepolymers.

If desired, the above-mentioned carboxybetaine polymer. may compriseonly a portion of the hinder, the remainder constituting gelatin or asecond synthetic polymer.

DETAILED DESCRIPTION OF THE INVENTION As indicated, the presentinvention is directed to photosensitive silver halide emulsions whereinphotosensitive silver halide crystals are disposed in a syntheticpolymeric binder comprising a water-soluble film-forming quaternaryammonium acrylate carboxybetaine polymer having in its structurerepeating units represented by the formula set forth above. The termfilm-forming is intended to designate a molecular weight sufficientlyhigh to form a film, for example, a molecular weight comparable to thatof gelatin (i.e., around 15,000).

Such polymers have been found to substantially meet all the basicrequirements for a gelatin substitute without possessing thedeficiencies of gelatin as delineated above. The emulsions of thepresent invention are more stable against degradation than gelatin;particularly against hydrolysis of the polymeric backbone in acidic orbasic media. This stability is due, in large part to the carboncarbonlinkages in the backbone of the instant polymers as opposed to therelatively easily hydrolyzable amide or ester linkages found in thepolymeric backbone of gelatin. The polymers of this invention also showa resistance to the growth of microorganisms which is not exhibited bygelatin.

As examples of monomers represented by the formula:

wherein R R R R R and R have the above-indicated definitions and whichare contemplated as being suitable for providing the quaternary ammoniumacrylate carboxybetaine polymers of the instant invention, mention maybe made of the following:

CH=CH c o e 3-[4-(meyanoacryloyloxy)-Nmethylpiperdiniuml-propionatebetaine I CHFC-CO O 011,:011-0 o 0 -I I CH;CH1C 0 o 9N-[2-(aeryloyloxy)cyelopropyl1-3-dlmethylammonium propionate betaineN-methyl-N-[fl-(aeryloyloxy)ethyl]-3-earboxypyrrolidine betaineCHz=CH-COOCH:CH:III CHrCOO C Ha N-methyl-N-[fi-(aeryloyloxy)ethyl1-4-carboxymethyl plperldlne betaine (B N-O H; O O O 9 CH;

CH2=C--C O [3'-(methaeryloyloxy)quinuclidinium1acetate beteine Theinstant polymers may be homopolymers or interpolymers having, inaddition to the repeating units defined above, any compatible repeatingunit or various repeating units which are not detrimental tophotographic silver halide emulsions and which allow the resultantpolymer to be soluble in water. Examples of typical comonomers which maybe employed in forming the polymers suitable for use in the presentinvention include the following ethylenically-unsaturated monomers:

( CHn=CH--COOH acrylic acid CH:=CC O OH methacrylic acid CHaCH=CH-C O OHcrotonie acid CHxCH=CH-C O OH isocrotonie acid ClCH=CH-C O OHfi-chlcroacryllc acid BrCH:=OH-C O OH fl-bromoaerylie acid C1GH=0C O OHB-ehloromethacrylie acid CHz=CH-C 0 0--CHa methyl acrylnte OH: CHz=(J-C0 O-CHzCHa ethyl methacrylate Cl CHz -C O D-GHzCHzC H;

n-propyl-a-ehloroaerylate BrCH=OH-O O OCH%%CH 7isopropyl-B-bromoacrylate CH;=CC O 0-CH2CH-{CHQ a isobutyl methacrylateCH2=G11-C 0 O-CH2CH2O H B-hydroxyethyl acrylate GH =CH-C O O-GHaCHzCHaOH a-hydroxypropyl acrylate CHFC"'C O OCH:CHCH;

2-hydroxy-n-propy1 methaerylate CH;=CHC 0NH aerylamide I C H2=CC O-NH:

a-ehloroacrylamide 1'31 CHFC-C O-NHz a-bromoaerylamide r CH2=CC 0-NH2methacrylamide C H; ClCH=(E-C 0-NH:

p-chloromethacrylamide N-(propionamidomethyl)methaerylamide CHz=CH-O CC-CHa vinyl acetate CH=CH0H (obtained by hydrolyzing (copolymerizedvinyl acetate vinyl acetate) CH2=C- 0 O C-CHzBr lsopropenyl bromoacetateCHFCH- O O C- C CHz) vinyl pivalate N-vinyl-tertiary butylcarbamatea-vinylluran aacryl0yloxymethyl/tetrahydroluran CHFCH-Q-OHp-hydroxystyrene C Hz=C H- m-hyd roxystyrene CH1=CH o-hydroxystyreneCH2=C H- C 0 0H p-carboxystyrene CHz=C1I- C O OH m-carboxystyrene C 0 OH o-carboxystyreue (96) CHFCHMNT N-vinyl-2-py1rolidone (97)CH2=CHCONH-CH2CH:

N-ethylacrylamlde (98) CHFCHCONHCHCH(CH3)2 C 0 O H N-acryloylvaline (99)CHFCH-CO-NH-CH-CHz-CHrS-CH:

C O O H N-acryloylmethionine (100) CHz=CH-C O-NH- CH-C.Hr-CHS -CH;

C 0 -N H:

N-acryloylmethionamide CHz=C--C ONHCH-CH:-CHz S -CH;

C O 0 H N-methacryloylmethlouine Polymerization of the indicatedmonomers is achieved by conventional free radical polymerizationtechniques.

The following non-limiting examples illustrate the preparation ofpolymers within the scope of the present invention. The numerical ratiobefore the word copolymer in the following examples refers to the molarratio of monomers in the reaction mixture forming the copolymer.

EXAMPLE 1 Poly N- [5- (methacryloyloxy) ethyl] -3-dimethylammoniumpropionate betaine A solution of 31.4 g. of dimethylaminoethylmethacrylate in 20.0 g. of methyl ethyl ketone was added to a solutionof 14.4 g. of fl-propicolactone in 20.0 g. of methyl ethyl ketone at -20C. This mixture was allowed to stand overnight at 20 C. The productformed was filtered and then polymerized in a 25% (by weight) solu tionusing, 0.1 g. of 2,2-azobis-[2-methylpropionitrile] in an evacuatedsealed tube at 70 C. for 17 hours. After diluting with methanol, thepolymer was precipitated from acetone, separated and dried to yield awhite flufiy solid soluble in water and alcohol.

9 EXAMPLE 2 1:1 copolymer of acrylamide/N-[fi-(methacryloyloxy)ethyl]-3-dimethylammonium propionate betaine 7.11 of acrylamide and22.93 g. of N- [fi-(methacryloyloxy) ethyl]-3-dimethylammoniumpropionate betaine were added to 300 mls. of distilled water in a 3-neckl-liter round-bottom flask with stirrer and under nitrogen. 10 mls. ofisopropanol were added and the pH adjusted to 6.4 with HNO or a 10% NaOHsolution, and then 0.05 g. of K S O was added. The solution was stirreduntil a clear viscous water-soluble liquid resulted. This liquid asanalyzed to have about 9.69% solids and a free acrylamide content ofabout 20.5 g./l.

EXAMPLE 3 1:1 copolymer of N isopropylacrylamide/N [,8-(methacryloyloxy)ethyl] 3 dimethylammonium propionate betaine Theprocedure of Example 2 was followed replacing the acrylamide with 11.32g. of N-isopropylacrylamide to yield a clear viscous water-solubleliquid which was analyzed to have 16.74% solids and a freeN-isopropylacrylamide content of about 2.69 g./ 1., with the othermonomer being present at less than 0.5 g./l.

EXAMPLE 4 9:1 copolymer of N isopropylacrylamide/N- [p-(methacryloyloxy)ethyl] 3-dimethylammonium propionate betaine 30.6 ofN-isopropylacrylamide and 6.88 g. of N-[fi- (methacryloyloxy)ethyl]3-dimethylammonium propionate betaine were reacted according to theprocedure of Example 2 to yield a clear viscous water-soluble liquid(below 32 C.) which was analyzed to have 10.16% solids and anN-isopropylacrylamide content of about 1.70 g./l. with the other monomerbeing present at least than 0.5 g./l.

EXAMPLE 5 1:1:1 terpolymer of Nisopropylacrylamide/N-[B-methacryloyloxy) ethyl]-3 dimethylammoniumpropionate betaine/ acrylamide The procedure of Example 2 was followedexcept that, in addition to the reagents already present, 11.32 g. of N-isopropylacrylamide was added to the polymerization solution, to yield aclear viscous water-soluble liquid which was analyzed to have about12.85% solids and an N-isopropylacrylamide content of 6.71 g./l. withthe content of the other monomers being present at less than 0.5 g./l.

EXAMPLE 6 Poly N- fi- (acryloyloxy) ethyl] -3-dimethyl ammoniumpropionate betaine 20 g. of N-[B-(acryloyloxy) ethyl]-3-dimethylammonium propionate betaine was polymerized in 60 g. of water using 0.1g. of 2,2'-azobis-[Z-methylpropionitrile] as catalyst in an evacuatedsealed tube at 70 C. for 17 hours. The resultant viscous liquid wasdiluted with methanol and precipitated in acetone to yield a whitefluffy solid.

EXAMPLE 7 7:3 copolymer of acrylamide/N-[fl-(acryloyloxy)ethyl]-B-dimethylammonium propionate betaine A solution was prepared comprising9.95 of acrylamide and 11.6 g. ofN-[fi-(acryloyloxy)ethyl]-3-dimethylammonium propionate betaine in 194mls. of distilled water and 2.2 mls. of isopropanol. The pH of thissolution was adjusted to about 6.4 with a 10% NaOH solution or diluteHNO and the solution was then polymerized with 0.01 g. of K S O and 0.01g. of NaHSO under nitrogen at 26 C. for 18 hours. A clear liquid ofmedium viscosity 10 was obtained which was analyzed to have 10.0%solids, a free acrylamide content of about 14.2 g./l. and about 0.8g./l. of free betaine monomer.

EXAMPLE 8 1:1 copolymer of acrylamide/N-[ti-(acryloyloxy)ethyl]-3-dimethylammonium propionate betaine The procedure of Example 7 wasfollowed employing 7.1 g. of acrylamide and 19.32 g. ofN-[fi-(acryloyloxy) ethyl]-3-dirnethylammonium propionate betaine in 238mls. of distilled water and 2.6 mls. of isopropanol, to yield a clearlow-viscosity liquid which was analyzed to have 13.1% solids, a freeacrylamide content of about 20.72 g./l. and about 8.9 g./l. freebetaine.

EXAMPLE 9 3:7 copolymer of acrylamide/N-[B-(acryloyloxy) ethyl]-3-dimethylammonium propionate betaine A solution of 3.2 g. of acrylamideand 20.3 g. of N-[p- (acryloyloxy)ethyl] 3 dimethylammonium propionatebetaine in 21 mls. of distilled water and 2.3 mls. of isopropanol wasadjusted to a pH of 6.4 with a 10% solution of NaOH or dilute HNO andthen polymerized under nitrogen for minutes at 6570 C. with 0.0075 g. ofK S O and 0.0075 g. of NaHSO to yield a clear liquid of medium viscositywhich was analyzed to have 8.3% solids, a free acrylamide content ofabout 4.93 g./l. and a free betaine monomer content of about 10.89 g./l.

EXAMPLE 10 9:1 copolymer of N-isopropylacrylamide/N-[ Q-(acryloyloxy)ethyl]-3-dimethylammonium propionate betaine 30.6 g. of N-isopropylacrylamide and 6.4 g. of N-[fl- (acryloyloxy)ethyl] 3 dimethylammoniumpropionate betaine were added to 300 mls. of distilled water undernitrogen in a 3-neck one-liter round-bottom flask with stirrer. 10 mls.of isopropanol were added and the pH adjusted to 6.4 with HNO or a 10%NaOH solution. 0.05 g. of K S O was added and the solution was stirreduntil viscous. The resultant liquid was analyzed to have 5.53% solidsand a free N-isopropylacrylamide content of 0.542 g./l. with freebetaine monomer content of less than 0.5 g./l.

The following general procedure may be used for preparing photographicemulsions using the above-described polymers of the instant invention asthe colloid binders.

A water-soluble silver salt, such as silver nitrate, may be reacted withat least one water-soluble halide, such as potassium, sodium, orammonium bromide, preferably together with potassium, sodium or ammoniumiodide, in an aqueous solution of the polymer. The emulsion of silverhalide thus-formed contains water-soluble salts, as a by-product of thedouble decomposition reaction, in addition to any unreacted excess ofthe initial salts. To remove these soluble materials, the emulsion maybe centrifuged and washed with distilled water to a low conductance. Theemulsion may then be redispersed in distilled water. To an aliquot ofthis emulsion may be added a known quantity of a solution of bodying orthickening polymer, such as polyvinyl alcohol having an averagemolecular weight of about 100,000 (commercially available from E. I. duPont de Nemours & Company, Wilmington, Del, designated Type 72-60). Asurfactant, such as dioctyl ester of sodium sulfosuccinic acid,designated Aerosol OT, (commercially available from Ameri can CyanamidCompany, New York, N.Y.), may be added and the emulsion coated onto afilm base of cellulose triacetate sheet having a coating of hardenedgelatin.

The emulsions may be chemically sensitized with sulfur compounds such assodium thiosulfate or thiourea, with reducing substances such asstannous chloride; with salts of noble metals such as gold, rhodium andplatinum; with amines and polyamines; with quaternary ammonium .1 1compounds such as alkyl u-picolinium bromide; and with polyethyleneglycols and derivatives thereof.

The polymers employed as the binders in the emulsions of the presentinvention may be cross-linked according to conventional procedures. Asan example, polymers may be ionically cross-linked with dibasic acids orcrosslinked with succinaldehyde.

The emulsions of the present invention may also be optically sensitizedwith cyanine and merocyanine dyes. Where desired, suitable antifoggants,toners, restrainers, developers, accelerators, preservatives, coatingaids, plasticizers, hardeners and/ or stabilizers may be included in thecomposition of the emulsion.

The emulsions of this invention may be coated and processed according toconventional procedures of the art. They may be coated, for example,onto various types of rigid or flexible supports, such as glass, paper,metal, and polymeric films of both the synthetic type and those derivedfrom naturally occurring products. As examples of specific materialswhich may serve as supports, mention may be made of paper, aluminum,polymethacrylic acid, methyl and ethyl esters, vinylchloride polymers,polyvinyl acetal, polyamides such as nylon, polyesters such as polymericfilm derived from ethylene glycol-terephthalic acid, and cellulosederivatives such as cellulose acetate, triacetate, nitrate, propionate,butyrate, acetate propionate, and acetate butyrate. Suitable subcoatsmay be provided on the supports, for example a layer of gelatin, ifnecessary or desirable for adherence, as is well known in the art.

The polymers employed in the practice of the instant invention maycontain from 5-100 mole percent of the above-indicated repeating units.The specific amount employed may be selected by the operator dependingupon the grain particle size and habit desired.

By selecting appropriate comonomers, the instant cpolymers may be madeto be compatible with all watersoluble bodying polymers. Emulsions madefrom these novel polymers, may be bodied with any water-solublepolymers, overcoming the disadvantage encountered with gelatin which isonly compatible with a very few polymers in a most limited pH range. Asexamples of specific materials which may serve as bodying polymers aregelatin, polyvinyl alcohol, polyacrylamide, polyalkylacrylamides,polyvinyl pyrrolidone, polymethacrylamidoacetamide, vinylalcohol/N-'vinylpyrrolidone copolymers, poly-N-ethylaziridine,poly-N-(Z-hydroxyethyl) aziridine, poly-N-(Z cyanoethyl) aziridine,poly(B-hydroxyethyl acrylate), polyethylene imine and cellulosederivatives such as hydroxyethyl cellulose, hydroxypropyl cellulose andmethyl cellulose. It has been found that using only a small amount of oneor more of the instant polymers, large amounts of photosensitive silverhalide grains may be obtained.

An emulsion made from one of these polymers of the instant invention maytherefore be bodied with a watersoluble polymer such that the polymericconstitution of the resulting emulsion comprises a relatively largepercentage of the bodying polymer.

By selecting appropriate comonomers, copolymers with selected diffusioncharacteristics may be prepared. For example, the rate of diffusion ofalkali ion or a dye-developer through an emulsion comprising one of thepolymers of this invention may be modified by varying the composition ofthe polymer.

The instant invention will be further illustrated by reference to thefollowing nonlimiting examples in which silver halide emulsions wereprepared employing the carboxybetaine polymers of Examples 1-3 and -9 asbinders:

EXAMPLE 11 A solution of 4.15 g. of the dry polymer (based on percentsolids if the polymer is a liquid) in 266 ml. of distilled water wasadjusted to pH 6.30 with dilute nitric acid and maintained at atemperature of 55 C. To this solution, 44.0 g. of dry potassium bromideand 0.50 g. of dry potassium iodide were added.

A solution of 55 g. of silver nitrate in 500' ml. of distilled water wasprepared. From this silver nitrate solution, 100 ml. was rapidly addedwith continuous agitation to the polymer-halide solution and theremainder was added over a period of 22 minutes. Thereafter, theemulsion was ripened for 30 minutes at 55 C., and then rapidly cooled tobelow 20 C.

Silver halide emulsions employing the polymers of Examples 4 and 10 asbinders were also prepared by the following procedure:

EXAMPLE 12 The procedure of Example 11 was followed except that theemulsions were ripened for minutes at 30 C. The addition of silvernitrate was also carried out at 30 C. for the emulsion employing thepolymer of Example 10. All emulsions contained octahedral plateletcrystals.

The following table summarizes the silver halide grain sizes obtained inthe emulsions prepared in the above examples.

TABLE 1 Grain size Microns, Examples Polymer range average 1 and 11.--.Poly N-[B-(methacryloyloxy)ethyl1- 0.1-0. 2 0. 5

3-d1methylammonium propionate betame. 2 and 11 1:1acrylamide/N-[B-(methacryloyl- 0. 5-1. 0 0. 7

oxy) l-3-dirnethylammonium propionate betaine. 3 and 11--.. 1:1N-isopropylacrylamide/N-[B- 0. 5-1. 0 0. 7

(methacryloyloxy) ethyl]-3-dimethylammonium propionate betaine. 4 and 129:1 copolymer of the above monomers- 0. 3-1. 2 O 6 4 and 1l 1:1:1N-isopropylacrylamide/N- 0. 3-0. 8 0 4 [d-(mothaeryloyloxy)ethyl]-3-dimethylammonium propionate betaine/aerylamide. 6 and 11..-. PolyN-[fi-(acryloyloxy)ethyl]-3- 0 1-0. 5 0. 3

dimethylammonium propionate betaine. 7 and 11 7:3acrylamide/NU9-(aeryloyloxy) 0 2-2. 0 0. 6

ethyl]-3-dimethylarnmonium propionate betaine. 8 and 11 1:1 copolymer ofthe above monomers. 0 2-1. 5 0.5 9 and 11. 3:7 copolymer of the abovem0nomers 0. 1-1. 0 0. 2 10 and 12--- 9:1 N-isopropylacrylamide/N-[B-0 1. 5 0. 7

(acryloyloxy)ethyl1-3-dimethylammonium propionate betalne. 13 Gelatin 0.2-1. 8 1. 0

EXAMPLE 14 The emulsion mixture of Example 11 employing the copolymer ofExample 7 was centrifuged and washed with water to a low conductance andthen redispersed in distilled water. To an aliquot of this emulsion wasadded a solution of bodying or thickening polymer of polyvinyl alcoholhaving an average molecular weight of about 100,000 (commerciallyavailable from E. I. du Pont de Nemours & Company; Wilmington, Del.,designated Type 72-60) to give a silver to bodying polymer ratio ofabout 120.74. Another aliquot received no bodying polymer solution. Asurfactant, Aerosol OT, was added and each emulsion aliquot was slotcoat-ed at various silver coverages onto a base of cellulose triacetatesheet 5 mils. thick subcoated with 30 mg./sq. ft. of hardened gelatin.This film so prepared was air dried, exposed on a sensitometer, andprocessed with a processing solution and an imagereceiving sheet from aPolaroid Type 107 Land film assembly (Polaroid Corporation, Cambridge,Mass.). The negative and image-receiving element were maintained insuperposed position for 10 seconds after which they were stripped apart.Alternatively, the processing was effected with a processing solutionand an image-receiving element from a Polaroid Type 42 Land film or aPolaroid Type 20C Land film. The photographic characteristics of theresulting positive prints were then measured by an auto- 13 maticrecording densitometer. The following table summarizes the densitometerreadings obtained on samples of these positive prints:

9. The product as defined in claim 7 wherein said first monomer is N-[B-(acryloyloxy)ethyl]-3-dimethylammonium propionate betaine.

TABLE 2 c! polymer Mg. Film Grain-growing polymer Bodyingpolymer ratio.Agzt. system Dm. Dmin. AD

7 s 1 d /N[fl( l None m $13 i (i128 :zacryamre--acryoyloxy)ethyl]-3-dimethyl- 10-74 {T-l07 0.41 0.15 0.26 ammoniumpropionate T-20C 1. 19 0. 41 0. 78 betaine. do 1:0.74 105.2 T-42 0.770.14 0.63 0.68 0.14 0.54

In certain photographic applications, it may be desirable to replacepart, but not all, of the gelatin in the photosensitive emulsion. Inview of the characteristics of these polymers described above, andfurther, in view of their compatibility with gelatin in substantiallyall proportions, it will be obvious that these polymers are ideallysuited for such use.

The term photosensitive and other terms of similar import are hereinemployed in the generic sense to describe materials possessing physicaland chemical properties which enable them to form usable images whenphotoexposed by radiation actinic to silver halide.

Since certain changes may be made in the above products and processeswithout departing from the scope of the invention herein involved, it isintended that all matter contained in the above description shall beinterpreted as illustrative only and not in a limiting sense.

What is claimed is:

1. A photosensitive silver halide emulsion wherein the emulsion bindercomprises a water-soluble film-forming polymer having in its structurerepeating units of the formula:

R1 B: it t 4 ha-r zi'imcoo wherein R is hydrogen, a lower alkyl group ora halogen; R is hydrogen, a lower alkyl group, halogen or cyano group; Rand R each is a lower alkylene or lower cycloalkylene group, and R and Reach is a lower alkyl or lower cycloalkyl group; or a combination of Rand/or R and/or R and/or R represents the atoms necessary to complete a3 to S-member heterocyclic ring structure.

2. The product as defined in claim 1 wherein substantially all of saidemulsion binder comprises said polymer.

3. The product as defined in claim 1 wherein said polymer comprises5-100 mole percent of said repeating units.

4. The product as defined in claim 1 wherein said silver halide emulsionis a silver iodobromide emulsion.

5. The product as defined in claim 1 wherein said emulsion includes atleast one chemical sensitizing agent.

6. The product as defined in claim 1 wherein said emulsion includes atleast one optical sensitizing agent.

7. The product as defined in claim 1 wherein said polymer comprises acopolymer of a first monomer of the formula:

and a second ethylenically unsaturated monomer.

8. The product as defined in claim 7 wherein said first monomer is N-[B-(methacryloyloxy)ethyl] -3-dimethylammonium propionate betaine.

10. The product as defined in claim 7 wherein said secone monomer isacrylamide.

11. The product as defined in claim 7 wherein said second monomer isN-isopropylacrylamide.

12. The product as defined in claim 1 which includes a bodying polymer.

13. The product as defined in claim 12 wherein said bodying polymer ispolyvinyl alcohol.

14. The product as defined in claim 12 wherein said bodying polymer isgelatin.

15. A photosensitive silver halide emulsion wherein the emulsion bindercomprises a water-soluble film-forming homopolymer consistingessentially of repeating units of the formula:

ari rimooo wherein R is hydrogen, a lower alkyl group or a halogen; R ishydrogen, a lower alkyl group, halogen or cyano group; R and R each is alower alkylene or lower cycloalkylene group, and R and R each is a loweralkyl or lower cycloalkyl group; or a combination of R and/or R and/or Rand/or R represents the atoms necessary to complete a 3 to S-memberedheterocyclic ring structure.

16. The product as defined in claim 15 wherein said homopolymer is polyN- [fi-(methacryloyloxy)ethyl]-3-dimethylammonium propionate betaine.

17. The product as defined in claim 15 wherein said homopolymer is polyN- [,3-(acryloyloxy)ethyl]-3-dimethylammonium propionate betaine.

18. A method of preparing a photosensitive silver halide emulsion whichcomprises reacting a water-soluble silver salt with a water-solublehalide salt in an aqueous solution containing a water-solublefilm-forming polymer having in its structure repeating units of theformula:

lilii. l

F... itaz i mooo wherein R is hydrogen, a lower alkyl group or ahalogen; R is hydrogen, a lower alkyl group, a halogen or cyano group; Rand R each is a lower alkylene or lower cyclo alkylene group, and R andR each is a lower alkyl group or lower cycloalkyl group; or acombination of R and/ or R and/or R and /or R represents the atomsnecessary to complete a 3 to 8-membered heterocyclic ring structure.

15 19. The method as defined in claim 18 wherein said polymer comprisesa copolymer of a first monomer of the formula:

and a second ethylenically unsaturated monomer.

20. The method as defined in claim 19 wherein said first monomer isN-[fl-(methacryloyloxy)ethyl] 3 dimethylammonium propionate betaine.

21. The method as defined in claim 19 wherein said first monomer isN[B-(acryloyloxy)ethyl] -3-dimethylammonium propionate betaine.

22. The method as defined in claim 19 wherein said second monomer isacrylamide.

23. The method as defined in claim 19 wherein said second monomer isN-isopropylacrylamide.

24. The method as defined in claim 18 wherein said aqueous solutionincludes a bodying polymer.

25. The method as defined in claim 24 wherein said bodying polymer ispolyvinyl alcohol.

26. The method as defined in claim 24 wherein said bodying polymer isgelatin.

27. A method of preparing a photosensitive silver halide emulsion whichcomprises reacting a water-soluble silver salt with a water-solublehalide salt in an aqueous solution containing a water-solublefilm-forming homopolymer consisting essentially of repeating units ofthe formula:

wherein R is hydrogen, a lower alkyl group or a halogen; R is hydrogen,a lower alkyl group, a halogen or cyano group; R and R each is a loweralkylene or lower cycloalkylene group, and R and R each is a lower alkylgroup or lower cycloalkyl group; or a combination of R and/ or R and/orR and/or R represents the atoms necessary to complete a 3 to 8-memberedheterocyclic ring structure.

28. The method as defined in claim 27 wherein said polymer is polyN-[,8-(methacryloyloxy)ethyl]-3-dimethylammonium propionate betaine.

29. The method as defined in claim 27 wherein said polymer is polyN-[,8-(acryloyloxy)ethyl]-3-dimethylammonium propionate betaine.

References Cited UNITED STATES PATENTS 3,749,577 7/1973 Hollister et a]961 14 2,839,401 6/1958 Gray et a1 961 14 3,411,912 11/1968 Dykstra eta1. 96ll4 3,709,690 1/ 1973 Cohen et a1. 961 14 FOREIGN PATENTS 553,5192/1958 Canada 961 14 598,942 5/1960 Canada 96-114 788,343 12/1957 GreatBritain 96-1 14 DAVID KLEIN, Primary Examiner R. L. SCHILLING, AssistantExaminer

